Bitwarden Authenticator is a standalone app that is available for everyone, even non-Bitwarden customers.
In its current release, Bitwarden Authenticator generates time-based one-time passwords (TOTP) for users who want to add an extra layer of 2FA security to their logins.
There is a comprehensive roadmap planned with additional functionality.
Available for iOS and Android
No, I use a different authenticator app (called Authenticator in the Flatpak store), but it does use the same keys. So I import the keys from an Aegis dump so I can generate exactly the same keys on my desktop app that I do on my phone.
TOTP is a really simple system, as long as I have access to the secret key and a reliable time source, I can generate the exact same tokens as any TOTP app would.